Appliance of Electron Beam Technology for Disinfection of Sewage Water to Minimize Public Health Risks

Article excerpt

1. Introduction

India faces a turbulent water future, unless water management practices are changed India will face a severe water crisis within the next two decades and will have neither the cash to build new infrastructure nor the water needed by its growing economy and rising population. Water is one of the critical inputs for the sustenance of mankind. Almost 70% of the water resources of India have been polluting due to the discharge of domestic sewage and industrial effluents into natural water source, such as rivers, streams as well as lakes [1]. About 95% of rural population living in India depends on ground water for domestic use and also for various activities [2],

Coliforms and Fungi are the prevalent in sewage rich environments. The waste water and sewage are rich in organic matter, are habitat for many microorganisms [3] and domestic sewage is a rich source of human excreta, keratin, cellulose and lignin etc. where the occurrence of pathogenic microorganisms can be easily expected.

In general, the qualitative and quantitative composition of coliforms can be multifunctional bioindicator of environmental pollution with sewage. It means that the composition indicates not only the presence of faecal contaminants in the environment but also respond to the changes in environmental conditions. Additionally, the fungal growth informs us about the infection risk associated with the contamination of the environment with potential fungal pathogens [4].

Recently, application of ionizing irradiation, especially electron beam radiation that is generated from electron beam accelerator to treat sewage water has attracted the environmentalists. It was reported that ionizing radiation induces both the degradation of numerous compounds and the inactivation of microorganisms in sewage on irradiation, depending on the type of energy and dose rate [5, 6 & 7].

Many disease-causing viruses, parasites, and bacteria also are present in wastewater and enter into community whenever possible. These pathogens often originate from people and animals that are infected with or are carriers of a disease. Graywater and blackwater from typical homes contain enough pathogens to pose a risk to public health. Other likely sources in communities include hospitals, schools, farms, and food processing plants. Some illnesses from wastewater-related sources are relatively common.

Sewage system has to be established to collect the waste material; however, providing sewers for the cities is not a complete solution of the problem of excreta disposal, because sewage disposal into water resources or land would actually lead to the spreading of intestinal diseases and other environmental hazards. The character and degree of wastewater treatment depend on the raw water whether it is from factories or residential, and also on the system used. If wastewater is to be used for irrigation of agriculture crops, in an instructed manner, including a high degree fruit and vegetables usually consumed uncooked, disinfection is necessary to inactivate the pathogens. Additional processes may be required to remove certain resistant protozoan or helminthes.

In water as well as wastewater, the principal component is water. Therefore, it would be expected that the effect of ionizing radiation might be dominated by interaction of radiation and water [8]. As far as pure water is concerned, when exposed to ionizing radiation, the radiolysis of water can be presented as following equation [9].

So if we consider pure water, each lOOeV absorbed by water will result in the generation of 2.7 radical OH*, 2.6 eaq~, 0.6 radical H+, 2.6H30+, 0.7 molecule of H202 and 0.45 molecule of H2 [10].

Powerful oxidizing and reducing species (e.g., OH, eaqA, H) and molecular products (e.g., H2, PPOj) are produced due to the interaction between radiation and water, so these chain reactions lead to the phenomenon as described earlier by Parker and Darby (1995) Sommers and Glenn (2006) and Maruthi et. …